Artificial eyelid dynamic aperture optical arrays for large scale coding elements with application in visible to MWIR

The use of coded apertures in a large area MWIR system introduces a number of difficulties including the effects of diffraction and other distortions not observed in shorter wavelength systems. A new approach is being developed that addresses the effects of diffraction while gaining the benefits of coded apertures, thus providing the flexibility to vary resolution, possess sufficient light gathering power, and achieve a wide field of view (WFOV). The photonic MEMS artificial eyelid array technology is currently being applied as the coded aperture in this program for surveillance enabling technology development. Speed, lifetime, packaging and scalability are all critical factors for the MEMS eyelid technology to determine system efficacy as well as military and commercial usefulness. The electronic eyelid is the fundamental addressable unit for adaptive code generation and will allow the system to multiplex in time for increased resolution. The proposed system consists of four subsystems in parallel with each subsystem consisting of four subapertures. Each sub-aperture contains an artificial eyelid array capable of 36 different, independent patterns of open 500μm eyelids corresponding to 36 different look directions. Dynamic aperture arrays were fabricated on both quartz and sapphire substrates for operation in the visible to MWIR. Both 8×8 and 40×40 element arrays were designed, fabricated, and tested with the capability of 4, 8, and 16 unique pattern combinations. Process and device improvements have been implemented to improve the yield of the MEMS arrays. In addition to mechanical evaluations, the eyelid arrays were tested optically to demonstrate the capability of multiple look directions.

Duke Scholars

Author Brian R. Stoner Electrical and Computer Engineering